aflatoxin has been shown to activate the K-ras oncogene. K-ras is a protein that relays signals from the cell's plasma membrane to the nucleus. Once in the nucleus, the signal leads to cell division. Mutation of the K-ras proto-oncogene by aflatoxin leads to the production of a protein that is 'activated'. Once activated, the ras signals to the nucleus never stop. The affected cell may continue to divide indefinitely. The activation of oncogenes is another step in cancer development.[3] For more information on ras click here.